1. Field of the Invention
This invention relates to circuit breakers of the type having a bimetal thermal trip element and more particularly to circuit breakers for distribution transformers to control moderate power distribution on feeder circuits. The disclosed circuit breaker is particularly adaptable for use with oil filled distribution transformers.
2. Description of the Prior Art
Transformers used in power distribution systems are generally associated with a protective device which prevents or limits current overload damage to the transformer and its associated apparatus. A completely self-protected transformer includes a circuit breaker on the secondary or low voltage side to protect against damage due to overload currents. The secondary circuit breaker disconnects the transformer from its load if the load current becomes dangerously high.
Commonly used circuit breakers incorporate a bimetal thermal trip and an instantaneous magnetic trip. For overload currents it is desirable that the circuit interruption be completed as rapidly as possible after initiation.